Php complex validation logic

Question

I need to validate an input from text area. It is complex and i'm unable to figure out how i can do it best? Can you guys help?

Input from the text area are basically host names or ips. The input can be of any of the following formats:

x.x.x.x (single IP)
x.x.x.x-x.x.x.x (range of IPs)
x.x.x.x/x.x.x.x (IP and mask)
x.x.x.x/xx (IP and CIDR)
URL (with or without http:// and https:// prefixes)
domain name in format: xxxxxxx.xxx

Also multiple values can be given, like: 192.168.1.1 192.168.1.2/192.168.1.4

I am able to get the lines of textbox using the following code:

$text = trim($targets);
$textAr = explode("\n", $text);
$textAr = array_filter($textAr, 'trim');

foreach ($textAr as $line) {


}

I am unable to proceed further. Please help.

Thanks, Dave

You can also use this great lib github.com/Respect/Validation — Nicklasos
– Nicklasos, Commented Aug 2, 2013 at 9:50
@sash Why did you remove my answer. I was just trying to help — sash
– sash, Commented Sep 20, 2013 at 12:25

Michael · Accepted Answer · 2013-08-02 11:23:44Z

2

If you don't mind being slightly loose on your validation, you can do something simple such as this:

function filter_fn($input)
{
    $input = trim($input);
    $regex_ip = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$/';
    $regex_range = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})-([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$/';
    $regex_cidr = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\/[0-9]{1,2})$/';
    $regex_sub = '/^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\/[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$/';

    if (filter_var($input, FILTER_VALIDATE_REGEXP, array('options' => array('regexp' => $regex_ip)))) {
        return $input;
    }

    if (preg_match($regex_range, $input)) {
        return $input;
    }

    if (preg_match($regex_cidr, $input)) {
         return $input;
    }

    if (preg_match($regex_sub, $input)) {
        return $input;
    }

    if (filter_var($input, FILTER_VALIDATE_URL)) {
        return $input;
    }

    if (filter_var('http://'.$input, FILTER_VALIDATE_URL)) {
        return $input;
    }

    return false;
}

$textAr = explode("\n", $text);
$textAr = array_filter($textAr, 'trim');
foreach ($textAr as $line) {
    $success = filter_var($line, FILTER_CALLBACK, array('options' => 'filter_fn'));
    if (!$success) {
        // It failed.
    } else {
        // It worked.
    }
}

Note that in my example, I used both preg_match and filter_var with FILTER_VALIDATE_REGEXP. Both are identical in this case, so that first filter_var could have just as easily been replaced with:

preg_match($regex_ip, $input)

Or, even:

filter_var($input, FILTER_VALIDATE_IP)

answered Aug 2, 2013 at 11:23

Michael

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2 Comments

sash Over a year ago

Thanks a lot. When you said, 'if i'm slightly loose on validation', what do you mean? Can you suggest me when this wouldn't work?

Michael Over a year ago

You will still need a little more validation if you, for instance, wanted to validate that an ipv4 address is actually valid. e.g. this will pass with 555.555.555.555, so you would need additional constraints for that. It really depends on your use-case whether or not this would work. As it stands now, it is quite basic and would work for simple validation.

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